Ultrasonic transducers for wire bonding and methods of forming wire bonds using ultrasonic transducers

ABSTRACT

A method of forming a wire bond using a bonding tool coupled to a transducer is provided. The method includes the steps of: (1) applying electrical energy to a driver of the transducer at a first frequency; and (2) applying electrical energy to the driver at a second frequency concurrently with the application of the electrical energy at the first frequency, the first frequency and the second frequency being different from one another.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of PCT Patent Application No.PCT/US2010/044976 filed Aug. 10, 2010, which claims the benefit of U.S.Provisional Application No. 61/233,237, filed Aug. 12, 2009, thecontents of both of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to the operation of a wire bondingmachine, and more particularly, to improved ultrasonic transducers andmethods of operating ultrasonic transducers in connection with theformation of wire bonds.

BACKGROUND OF THE INVENTION

In the processing and packaging of semiconductor devices, wire bondingcontinues to be the primary method of providing electricalinterconnection between two locations within a package (e.g., between adie pad of a semiconductor die and a lead of a leadframe). Morespecifically, using a wire bonder (also known as a wire bonding machine)wire loops are formed between respective locations to be electricallyinterconnected. Wire bonding machines may also be used to formconductive bumps (which bumps may, or may not, be used in connectionwith wire loops).

An exemplary conventional wire bonding sequence includes: (1) forming afree air ball on an end of a wire extending from a bonding tool; (2)forming a first bond on a die pad of a semiconductor die using the freeair ball; (3) extending a length of wire in a desired shape between thedie pad and a lead of a leadframe; (4) stitch bonding the wire to thelead of the leadframe; and (5) severing the wire. In forming the bondsbetween (a) the ends of the wire loop and (b) the bond site (e.g., a diepad, a lead, etc.) varying types of bonding energy may be usedincluding, for example, ultrasonic energy, thermosonic energy,thermocompressive energy, amongst others.

U.S. Pat. No. 5,595,328 (titled “SELF ISOLATING ULTRASONIC TRANSDUCER”);U.S. Pat. No. 5,699,953 (titled “MULTI RESONANCE UNIBODY ULTRASONICTRANSDUCER”); U.S. Pat. No. 5,884,834 (titled “MULTI-FREQUENCYULTRASONIC WIRE BONDER AND METHOD”); and U.S. Pat. No. 7,137,543 (titled“INTEGRATED FLEXURE MOUNT SCHEME FOR DYNAMIC ISOLATION OF ULTRASONICTRANSDUCERS”) relate to ultrasonic transducers and are hereinincorporated by reference in their entirety. Ultrasonic bonding energyis typically applied using an ultrasonic transducer, where the bondingtool is attached to the transducer. The transducer typically includes adriver such as a stack of piezoelectric elements (e.g., piezoelectriccrystals, piezoelectric ceramics, etc.). Electrical energy is applied tothe driver, and converts the electrical energy to mechanical energy,thereby moving the bonding tool tip in a scrubbing motion. Thisscrubbing motion of the bonding tool tip is typically linear motionalong the longitudinal axis of the transducer.

It would be desirable to provide improved transducers for use inconnection with wire bonding machines, and improved methods of formingwire bonds using transducers.

SUMMARY OF THE INVENTION

According to an exemplary embodiment of the present invention, a methodof forming a wire bond using a bonding tool coupled to a transducer isprovided. The method includes the steps of: (1) applying electricalenergy to a driver of the transducer at a first frequency; and (2)applying electrical energy to the driver at a second frequencyconcurrently with the application of the electrical energy at the firstfrequency, the first frequency and the second frequency being differentfrom one another.

According to another exemplary embodiment of the present invention,another method of forming a wire bond using a bonding tool coupled to atransducer is provided. The method includes the steps of: (1) applyingelectrical energy to a driver of the transducer at a first frequency todrive a tip of the bonding tool in a first direction; and (2) applyingelectrical energy to the driver at a second frequency to drive a tip ofthe bonding tool in a second direction, the first direction beingdifferent than the second direction.

According to another exemplary embodiment of the present invention, atransducer for use in a wire bonding operation is provided. Thetransducer includes an elongated body portion configured to support abonding tool. The transducer also includes a driver for providingvibration to the elongated body portion, the driver including aplurality of piezoelectric elements, each of the plurality ofpiezoelectric elements being separated into at least two regionselectrically isolated from one another.

According to another exemplary embodiment of the present invention, atransducer for use in a wire bonding operation is provided. Thetransducer includes an elongated body portion configured to support abonding tool. The transducer also includes a driver for providingvibration to the elongated body portion, the driver being configured toreceive electrical energy and to provide a non-linear scrub of a tip ofthe bonding tool.

According to another exemplary embodiment of the present invention, atransducer for use in a wire bonding operation is provided. Thetransducer includes an elongated body portion configured to support abonding tool. The transducer also includes a driver for providingvibration to the elongated body portion, the driver including at leastone piezoelectric element configured to deform in a first direction uponthe application of electrical energy, and at least one piezoelectricelement configured to deform in a second direction upon the applicationof electrical energy, the first direction and second direction beingdifferent from one another.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed descriptionwhen read in connection with the accompanying drawing. It is emphasizedthat, according to common practice, the various features of the drawingare not to scale. On the contrary, the dimensions of the variousfeatures are arbitrarily deformed or reduced for clarity. Included inthe drawing are the following figures:

FIG. 1 is a perspective view of a transducer of a wire bonding machineand related components useful in explaining various exemplaryembodiments of the present invention;

FIGS. 2A-2B are front and back perspective views of a piezoelectricelement for use in a transducer in accordance with an exemplaryembodiment of the present invention;

FIG. 2C is a front view of the piezoelectric element of FIGS. 2A-2B;

FIG. 2D is a front view of an shim electrode for use in connection witha transducer in accordance with an exemplary embodiment of the presentinvention;

FIGS. 3A-3C and FIG. 4A are block diagram views of piezoelectric elementstacks for use in a transducer in accordance with exemplary embodimentsof the present invention;

FIG. 4B is a block diagram view of a portion of a device to be wirebonded using transducers in accordance with exemplary embodiments of thepresent invention;

FIG. 4C includes a plurality of block diagram views of piezoelectricelements useful in transducers in accordance with exemplary embodimentsof the present invention;

FIGS. 4D-4J are block diagram views of piezoelectric element stacks foruse in a transducer in accordance with exemplary embodiments of thepresent invention;

FIGS. 5A-5B are views of another piezoelectric element stack for use ina transducer in accordance with an exemplary embodiment of the presentinvention;

FIGS. 6A-6B are two views of additional configurations of apiezoelectric element stack for use in a transducer in accordance withadditional exemplary embodiments of the present invention; and

FIGS. 7A-7C are diagrams of scrub patterns of bonding tool tips inaccordance with exemplary embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to various improvements in the operationand/or design of transducers for use in connection with wire bondingoperations. According to certain exemplary embodiments of the presentinvention, an ultrasonic transducer of a wire bonding machine operatessimultaneously at two or more modes (i.e., two or more frequencies ofelectrical energy are applied to the driver of the transducer at thesame time). Simultaneous application of multiple frequencies may resultin a non-linear scrub of the tip of the bonding tool. For example, thenon-linear vibrational pattern may be a Lissajous type pattern such as acircular pattern, an elliptical pattern, or a mesh shaped pattern. Thescrub pattern may be planar (i.e., substantially planar at the bondingheight) or three dimensional (i.e., non-planar at the bonding height).

An exemplary technique for such a transducer is to segment theindividual electrodes of the piezoelectric elements (e.g. crystals),thereby forming at least two electrically isolated regions in eachelement. For example, the piezoelectric element stack can provideefficient excitation with the segmentation to closely match theindependent vibrational mode shape at its particular operatingfrequency. For example, a yaw bending mode produces scrubbing at the tipof the bonding tool along an X-axis of the wire bonding machine, and alongitudinal mode produces scrubbing at the tip of the bonding toolalong a Y-axis of the wire bonding machine. The transducer may alsoprovide one-dimensional independent, or sequential motion, by operatingsolely at any one of these operating modes/frequencies.

Through certain of the exemplary embodiments of the present inventionprovided herein, multidirectional (i.e., non-linear) vibrationalscrubbing energy is applied to the tip of the bonding tool, therebyresulting in less deformation or collateral damage to the bonded regionsadjacent to the welded surfaces. In comparison to conventionaltechniques, the multidirectional scrubbing motion may result in moreuniform bonded balls in both the X and Y bond plane directions, andhigher shear strength per unit area for a given ball size. Themultidirectional scrubbing motion may also be beneficial in wire bondingapplications that are particularly sensitive to pad splash damage in thedirection of scrubbing (e.g., copper wire bonding on aluminum pads,amongst others). That is, using multidirectional scrubbing, the padsplash can be more equally distributed around the wire bond (e.g., ballbond).

Additionally, certain exemplary embodiments of the present inventionprovide independent one-dimensional vibrational energy in a selected oneof a plurality directions, for example, to align with device geometriessuch as wires or lead fingers. By providing for such one-dimensionalvibrational energy in the desired direction depending on the bondlocation (e.g, selecting the direction depending upon the shape of thebonding location) to align with device geometries such as wires or leadfingers tends to provide more consistent energy delivery, and tends toreduce resonant vibrational effects from a given device.

Referring now to FIG. 1, a perspective view of ultrasonic transducer 100is provided (where transducer 100 has an elongated body portionextending along axis “A”). Transducer 100 includes mounting flanges 102a and 102 b used to mount transducer 100 to a bond head of a wirebonding machine. Piezoelectric elements 104 a, 104 b, 104 c, and 104 d(e.g., piezoelectric crystals, piezoelectric ceramics, etc.) arearranged in a stack in an aperture defined by the body portion oftransducer 100. The stack of piezoelectric elements 104 a, 104 b, 104 c,and 104 d is a driver for transducer 100. The elements are separated byconductive shim electrodes 106 a, 106 b, 106 c, and 106 d. Electricalenergy at a given frequency is applied to terminals 108 a and 108 b(e.g., 108 a is a positive terminal and 108 b is a negative terminal),thereby applying electrical energy to shim electrodes 106 a, 106 b, 106c, and 106 d. The application of the electrical energy at the givenfrequency causes expansion and contraction of the elements, therebyresulting in scrubbing of tip 110 a of bonding tool 110 along axis “A”(e.g., the Y-axis of a wire bonding machine). However, in certainapplications, it would be desirable to have more flexibility inselecting a scrub in multiple directions for the transducer as opposedto a conventional unidirectional (Y-axis) scrub. In other applicationsit would be desirable to vary the scrub direction depending upon theshape/configuration of the bonding location (e.g., the bond pad, thelead, etc.). While FIG. 1 illustrates a “unibody” style transducer withan aperture for housing the driver (the stack of crystals), theteachings of the present invention may be applied to other transducerdesigns such as “horn” style transducers (e.g., where the driver isprovided at an end of the transducer body away from the bonding tooltip), amongst others.

FIG. 2A is a perspective front view of element 204 a, and FIG. 2B is aperspective rear view of element 204 a. The front surface of element 204a is a positive electrode (e.g., a conductive electrode formed of amaterial such as, for example, silver, nickel, amongst other materials),and the rear surface of element 204 a is a negative electrode. Incontrast to elements 104 a, 104 b, 104 c, and 104 d shown in FIG. 1, thepositive electrode of element 204 a is divided by notch/groove 204 a 3,and the negative electrode of element 204 a is divided by notch/groove204 b 3. Thus, the positive electrode is divided into two electricallyisolated regions 204 a 1 and 204 a 2, and the negative electrode isdivided into two electrically isolated regions 204 b 1 and 204 b 2.Thus, electrical energy may be applied to the element through twoelectrically isolated paths (i.e., a first path is between regions 204 a1 and 204 b 1, and a second path is between regions 204 a 2 and 204 b2). As will be explained below, the division of the piezoelectricelements into electrically isolated regions allows for application ofmultiple frequencies of electrical energy to be applied to the driver ata given time, thereby yielding a desirable scrubbing motion at the tipof a bonding tool.

FIG. 2C is a front view of element 204 a. FIG. 2D is a front view ofelectrode 206 a which can be positioned between adjacent piezoelectricelements in a stack in an aperture of a transducer. Similar to element204 a, shim electrode 206 a is divided into two electrically isolatedregions. In FIG. 2D an insulative region 206 a 3 divides conductiveregion 206 a 1 from conductive region 206 a 2.

FIG. 3A is a top view block diagram illustration of a stack ofpiezoelectric elements which could be arranged in an aperture of atransducer (similar to the arrangement of elements 104 a, 104 b, 104 c,and 104 d in the aperture of transducer 100 in FIG. 1). The stackincludes element 204 a from FIGS. 2A-2C, and three similar elements 204b, 204 c, and 204 d. Each of elements 204 a, 204 b, 204 c, and 204 dhave their respective electrodes divided as is illustrated at the centerregion of each element. The stack also includes shim electrode 206 afrom FIG. 2D, as well as shim electrodes 206 b, 206 c, 206 d, and 206 e.In this particular configuration, only the positive shim electrodes aresplit (i.e., 206 a and 206 c), and the negative shim electrodes are allelectrically bonded together (e.g., to ground). FIGS. 3B and 3C are twodifferent examples of how the stack of FIG. 3A could be connected toelectrical signals. Referring specifically to FIG. 3B, a first frequencyf1 is electrically coupled to the right hand portion of the stack, whilesecond frequency f2 is electrically coupled to the left hand portion ofthe stack. Of course, f1 and f2 may be any desired frequencies given theapplication, transducer, and the desired scrub. Exemplary frequenciesfor f1 and f2 are 115 kHz and 120 kHz. As is shown in FIG. 3B, thepositive connection for frequency f1 (+f1) is electrically coupled tothe right hand portions of shim electrodes 206 a and 206 c. Likewise,the negative connection for frequency f1 (−f1) is electrically coupledto shim electrodes 206 b, 206 d, and 206 e. The positive connection forfrequency f2 (+f2) is electrically coupled to the left hand portions ofshim electrodes 206 a and 206 c. Likewise, the negative connection forfrequency f2 (−f2) is electrically coupled to shim electrodes 206 b, 206d, and 206 e. By applying these two frequencies f1, f2 to the respectivepiezoelectric element regions simultaneously, a non-linear scrub isapplied at the tip of the bonding tool coupled to the transducer.

FIG. 3C is another exemplary configuration of the crystal stack of FIG.3A. In contrast to FIG. 3B, both frequency f1 and f2 (+f1/f2, −f1/f2)are applied to both the left hand region and the right hand region ofthe crystals via the electrodes. These electrical signals, atfrequencies f1 and f2, are applied simultaneously; however, the phaseconfiguration of the signals may be changed to achieve the desiredresult. For example, the signals at frequency f1 at both regions (i.e.,the left hand and right hand regions) of the piezoelectric elements maybe in phase with one another; however, the signals at frequency f2 atboth regions (i.e., the left hand and right hand regions) of theelements may be out of phase with one another (e.g., 180 degrees out ofphase with one another) to achieve the desired result. As with FIG. 3B,this configuration may provide a non-linear scrub at the tip of thebonding tool such as a Lissajous type scrubbing motion.

FIG. 4A illustrates another exemplary configuration of piezoelectricelements in a transducer. In this example, the elements are providedsuch that they deform (e.g., expand, distort, twist, etc.) in differingdirections. In this example, elements 404 a and 404 b (the upper twopiezoelectric elements in FIG. 4A) deform such that they collectivelyprovide a scrub of the tip of the bonding tool in a first direction(e.g., the y direction (Y MOTION)), and elements 404 c and 404 d (thelower two piezoelectric elements in FIG. 4A) are configured to provide ascrub of the tip of the bonding tool in a second direction (e.g., the xdirection (X MOTION)) that is different from the first direction. Thefrequencies applied to the piezoelectric element group (i.e.,frequencies f1 and f2) may be different or they may be the same.

In the following description related to FIGS. 4A-4J (and applicable toother drawings as well), it should be understood that piezoelectricelement deformation (e.g., expansion, distortion, etc.) in a givendirection does not necessarily equate with scrubbing of the tip of thebonding tool in that direction. Rather, use of piezoelectric elementsthat deform in differing directions (e.g., in combination with otherfeatures such as split piezoelectric elements, split piezoelectricelement electrodes, etc.) efficiently enables desired modes oftransducer operation. For example, by applying electrical energy at tworesonant frequencies inherent to a transducer (to a single driver ofthat transducer) a desired non-linear scrubbing motion of the bondingtool tip may be achieved. It shall be appreciated that the electricalenergy at the two resonant frequencies may be applied to differentportions of the driver (e.g., to elements which deform in differingdirections) as illustrated and described herein.

In the illustrated example, the upper two piezoelectric elementscollectively provide a Y scrub of the bonding tool tip (i.e., along axis“A” shown in FIG. 1), while the lower two piezoelectric elementscollectively provide an X scrub of the bonding tool tip (i.e.,perpendicular to axis “A” shown in FIG. 1). It is understood that inthis example, element 404 a may not provide the Y scrub by itself, butcollectively, elements 404 a and 404 b efficiently excite the Y scrubvibrational mode of the transducer. Additionally, it is understood thatthe scrub directions are not limited to X and Y (where the X and Ydirections are perpendicular to one another) but could be any twodirections that are different from one another. Of course, in manyconventional wire bonding applications bond pads on a die andcorresponding leads on a leadframe tend to be aligned along one of theX-axis and the Y-axis, so such an arrangement may be particularlydesirable.

FIG. 4B illustrates a portion of exemplary semiconductor device 410(e.g., a semiconductor die 410, a leadframe 410, etc.). Device 410includes a first plurality of bonding locations 410 a (e.g., bond pads410 a, leads 410 a, etc.) arranged in a row, and a second plurality ofbonding locations 410 b (e.g., bond pads 410 b, leads 410 b, etc.)arranged in a column that is generally perpendicular to the row ofbonding locations 410 a. As made clear in FIG. 4B, the shape of bondinglocations 410 a, 410 b is not square, but rather, is rectangular. Insuch a case, it may be desirable to form wire bonds on the bondinglocations 410 a, 410 b using scrubbing motions that depend on the shapeof the given bonding location. That is, when bonding a portion of wireto bonding location 410 a (e.g., to form a wire bond of a wire loop,such as a first bond or a second bond of the wire loop) it may bedesired to configure the transducer to provide scrubbing of the bondingtool tip along the Y-axis (e.g., see the legend). Likewise, when bondinga portion of wire to bonding location 410 b it may be desired toconfigure the transducer to provide scrubbing of the bonding tool tipalong the X-axis.

Of course, the shape of the bonding locations is not the only reason tovary the scrubbing direction. Another exemplary reason relates to diepad splash or related problems. As will be understood by those skilledin the art, semiconductor device manufacturers continue to strive toreduce the size of devices, and as such, they strive to reduce thespacing between bonding locations (e.g., between adjacent die pads).However, such reduced spacing between bonding locations increases thepotential for pad splash causing electrical shorting. The potential forsuch pad splash shorting is made worse still, for example, when copperwire is used to form the wire bonds due to the work hardening of acopper. Again, referring to FIG. 4B, when bonding a portion of wire tobonding location 410 a it may be desired to configure the transducer toprovide scrubbing of the bonding tool tip along the Y-axis such that thescrubbing is not in the direction of an adjacent bonding location 410 a(where bonding locations 410 a are arranged in a row along the X-axis),thereby reducing the potential for pad splash with adjacent bondinglocations 410 a. Likewise, when bonding a portion of wire to bondinglocation 410 b, by configuring the transducer to provide scrubbing ofthe bonding tool tip along the X-axis such that the scrubbing is not inthe direction of an adjacent bonding location 410 b (where bondinglocations 410 b are arranged in a column along the Y-axis), thepotential for pad splash with adjacent bonding locations 410 b isreduced.

Referring now to the electrical connections in FIG. 4A, the positiveconnection for first frequency f1 is provided to the positive electrodeof elements 404 a and 404 b (i.e., the electrode labelled 406 a in FIG.4A), and the negative connection for first frequency f1 is provided tothe negative electrode of elements 404 a, 404 b (i.e., by bonding of thenegative electrodes to ground). Likewise, the positive connection forsecond frequency f2 is provided to the positive electrode of elements404 c and 404 d (i.e., the electrode labelled 406 c in FIG. 4A), and thenegative connection for second frequency f2 is provided to the negativeelectrode of element 404 c, 404 d (i.e., by bonding of the negativeelectrodes to ground). Of course, the negative connections for bothfrequencies may be bonded together, and grounded, as illustrated (i.e.,the connections to electrodes 406 b, 406 d, and 406 e, may be bondedtogether, and coupled to ground if desired).

In FIG. 4A, frequency signal f1 is labelled as f1 _(T1), and frequencysignal f2 is labelled as f2 _(T2) where “T” is time. This is because theelectrical signals at frequencies f1 and f2 may not be appliedsimultaneously. Of course, the signals could be applied simultaneously,but in the example presently described they are sequentially applied aswill be described in the operational sequence below.

Now an exemplary, non-limiting, operational sequence is described forFIG. 4A. In this exemplary application, let us assume that we arebonding wire loops between a conventional die (with bond pads in asquare configuration around the periphery of the die) and a leadframesupporting the die (with leads in a square configuration). In such anexample, wire loops may be extended in one of two directions, that is,along the X-axis or the Y-axis. It may be desirable that the wire bonds(e.g., the first bonds and/or second bonds) of the wire loops formedalong the X-axis be formed with an X-axis scrub (X MOTION), and that thewire bonds of the wire loops formed along the Y-axis be formed with aY-axis scrub (Y MOTION). Referring now to FIG. 4A, when forming thefirst groups of wire loops along the Y-axis, electrical energy atfrequency f1 is applied at time T1 (i.e., f1 _(T2)). As described above,the application of this electrical energy desirably results in theY-axis scrub of the bonding tool tip. After the first group of wireloops is formed, the second group of wire loops is to be formed alongthe X-axis. In forming this second group of wire loops, electricalenergy at frequency f2 is applied at time T2 (i.e., f2 _(T2)). Asdescribed above, the application of this electrical energy desirablyresults in the X-axis scrub of the bonding tool tip. While this examplehas been described in connection with two groups of wire loops along theX-axis and Y-axis respectively, other alternatives are contemplated. Forexample, more than two groups of wire loops may be formed (e.g., firstwire loops along the Y-axis using f1, then wire loops along the X-axisusing f2, then wire loops along the Y-axis again using f1, etc.).Further, the direction of tool tip scrub may be different than justX-axis or Y-axis scrub. For example, additional or different scrubs arepossible (e.g., by providing crystals that deform in differentdirections, at the same or different frequencies, to generate additionalor different tool tip scrub directions).

Further still, during formation of a single wire bond (e.g., a ballbond, a stitch bond, etc.) scrubbing along more than one direction maybe employed. For example, scrubbing along the X-axis may be used,followed by scrubbing along the Y-axis, during formation of the samewire bond. Of course, other scrubbing directions are contemplated.

It is understood that the order of the piezoelectric elements used togenerate the first scrub and the second scrub may be different from thatillustrated in FIG. 4A. More specifically, in FIG. 4A, the upper twoelements (404A, 404B) collectively generate the Y-axis scrub, and thelower two elements (404C, 404D) generate the X-axis scrub. However, theinvention is not so limited. Any combination of piezoelectric elementsmay be used to generate the desired scrub (e.g., the first and thirdelements could generate a first scrub, while the second and fourthelements could generate a second different scrub). Likewise, differentnumbers of piezoelectric elements may be provided in the transducer.

Additionally, while not shown in FIG. 4A, if desired to achieve aspecific result, the piezoelectric element electrodes in theconfiguration of FIG. 4A may be split as are elements 204 a, 204 b, 204c, 240 d shown in FIG. 3A. Further, the electrical energy at themultiple frequencies may be applied simultaneously where T1=T2 (insteadof sequentially). Further still, the electrical energy at the multiplefrequencies may be applied to each group of crystals, with or without aphase shift between certain of the frequencies.

As provided above with respect to FIG. 4A, the piezoelectric elements ina given piezoelectric element stack (where the stack is a single driverof a transducer such as transducer 100 in FIG. 1) are provided such thatthey deform in differing directions. FIG. 4C illustrates four elements420, 422, 424, and 426. Element 420 is a piezoelectric element in anon-energized state, illustrated for reference only. Element 422 is apiezoelectric element that deforms in the y direction (e.g., expands inthe y direction, along the Y-axis of a wire bonding machine), and assuch, during application of electrical energy, the element deforms inthe y direction to include deformed areas 422 a and 422 b. Element 424is a piezoelectric element that deforms in the x direction (e.g.,expands in the x direction, along the X-axis of a wire bonding machine),and as such, during application of electrical energy, the elementdeforms in the x direction to include deformed areas 424 a and 424 b.Element 426 is a piezoelectric element that deforms in an XY sheardirection (e.g., distorts in the XY shear direction of a wire bondingmachine), and as such, during application of electrical energy, theelement deforms in the XY shear direction to include deformed areas 426a and 426 b. Element 426 also illustrates an exemplary polarity and acorresponding XY shear deformation direction indicated by an arrow inelement 426. As will be appreciated by those skilled in the art,piezoelectric elements that deform in differing directions may becombined in a single driver of a transducer (e.g., in a singlepiezoelectric element stack). In order to provide the desired effect(e.g., a given non-linear scrub of the bonding tool tip, selectivelinear scrub in a first direction for formation of certain wire bonds,and in a second direction for formation of other wire bonds), variousfeatures may be varied, for example: the transducer design; a driverincluding piezoelectric elements that deform in different directions;application of multiple frequencies simultaneously to the driverpiezoelectric elements; application of multiple frequenciessequentially; split piezoelectric element electrodes; amongst others.

FIGS. 4D-4J illustrate a number of exemplary configurations combiningpiezoelectric elements that deform in different directions. In FIGS.4D-4J piezoelectric elements labelled “Y” are elements that areconfigured to deform in the y direction, and piezoelectric elementslabelled “XY SHEAR” are elements configured to deform in the XY sheardirection. Unless indicated otherwise, in any of the examplesillustrated in FIGS. 4D-4J, electrical energy at frequency f1 and f2 maybe provided simultaneously, separately, and/or sequentially, as desired,to achieve the desired bonding tool tip scrub. The piezoelectric elementstack configuration illustrated in FIGS. 4D-4J may be used, for example,to achieve a desired non-linear tool tip scrub, a selective linear tooltip scrub (scrubbing along the X-axis for certain bonding locations, andscrubbing along the Y-axis for other bonding locations, scrubbingsequentially along one of the x & y directions, and then the other ofthe x & y directions, in the same wire bond), etc.

FIG. 4D illustrates a driver for use in a transducer including a stackof elements 434 a (a piezoelectric element that deforms in the XY sheardirection), 434 b (a piezoelectric element that deforms in the Ydirection), 434 c (a piezoelectric element that deforms in the Ydirection), and 434 d (a piezoelectric element that deforms in the XYshear direction), where elements 434 a, 434 b are separated by shimelectrode 436 a; elements 434 b, 434 c are separated by shim electrode436 b; elements 434 c, 434 d are separated by shim electrode 436 c; shimelectrode 436 d is adjacent element 434 d; and shim electrode 436 e isadjacent element 434 a. The positive connection for both frequencies f1,f2 (+f1/f2) is provided to the positive electrode of elements 434 a and434 b (i.e., the shim electrode labelled 436 a in FIG. 4D), and to thepositive electrode of elements 434 c and 434 d (i.e., the shim electrodelabelled 436 c in FIG. 4D). The negative connection for both frequenciesf1, f2 (−f1/f2) is provided to the negative electrode of elements 434 a,434 b, 434 c, and 434 d (i.e., the shim electrodes labelled 436 b, 436d, and 436 e in FIG. 4D), and may be grounded as desired. Electricalenergy at frequency f1 and f2 may be provided simultaneously,separately, and/or sequentially, as desired, to achieve the desiredbonding tool tip scrub. The piezoelectric element stack configurationillustrated in FIG. 4D may be used, for example, to achieve a desirednon-linear tool tip scrub, a selective linear tool tip scrub (i.e.,scrubbing along the x-axis for certain bonding locations, and scrubbingalong the y-axis for other bonding locations), etc.

FIG. 4E illustrates a driver for use in a transducer including a stackof piezoelectric elements 444 a, 444 b, 444 c, and 444 d, where elements444 a, 444 b are separated by shim electrode 446 a; elements 444 b, 444c are separated by shim electrode 446 b; elements 444 c, 444 d areseparated by shim electrode 446 c; shim electrode 446 d is adjacentelement 444 d; and shim electrode 446 e is adjacent element 444 a.Elements 444 b, 444 c have their electrodes split, and shim electrode446 b is a split shim electrode. The positive connection for bothfrequencies f1, f2 (+f1/f2) is provided to shim electrodes 446 a, 446 c.The negative connection for both frequencies f1, f2 is provided toelectrodes 446 d, 446 e, to the left hand portion of shim electrode 446b, and to the right hand portion of shim electrode 446 b, where thenegative connections may be grounded as desired. In such an example,shim electrode 446 b is split with separate ground wires allowing forindependent current flow from either side of the piezoelectric element.

FIG. 4F illustrates a driver for use in a transducer including a stackof piezoelectric elements 454 a, 454 b, 454 c, and 454 d, where elements454 a, 454 b are separated by shim electrode 456 a; elements 454 b, 454c are separated by shim electrode 456 b; elements 454 c, 454 d areseparated by shim electrode 456 c; shim electrode 456 d is adjacentelement 454 d; and shim electrode 456 e is adjacent element 454 a.Elements 454 b, 454 c have their electrodes split, and shim electrode456 b is a split electrode. The positive connection for both frequenciesf1, f2 (+f1/f2) is provided to shim electrodes 456 a, 456 c, and to theright hand portion of split shim electrode 456 b. The negativeconnection for both frequencies f1, f2 (−f1/f12) is provided to shimelectrodes 456 d, 456 e, and to the left hand portion of shim electrode456 b, where the negative connections may be grounded as desired. Insuch an example, the shorting of both of the right side electrodes(positive and negative) of element 454 c substantially eliminates theoutput for both f1/f2 modes.

While the embodiments described thus far have included 4 piezoelectricelements (e.g., piezoelectric crystals, piezoelectric ceramics, etc.) ina driver stack, the invention is not so limited. In fact, any number ofelements may be included in a driver, as desired in the givenapplication. In FIGS. 4G-4J, eight piezoelectric elements are providedin each driver stack. In FIGS. 4G-4J, none of the elements have theirelectrodes split, and none of the electrodes are split; however, it isunderstood that in certain implementations of the invention suchelements may have their electrodes split, and such electrodes may besplit, as desired.

FIG. 4G illustrates a driver for use in a transducer including a stackof piezoelectric elements 464 a, 464 b, 464 c, 464 d, 464 e, 464 f, 464g, and 464 h. Elements 464 a, 464 b are separated by shim electrode 466a; elements 464 b, 464 c are separated by shim electrode 466 b; elements464 c, 464 d are separated by shim electrode 466 c; elements 464 d, 464e are separated by shim electrode 466 d; elements 464 e, 464 f areseparated by shim electrode 466 e; elements 464 f, 464 g are separatedby shim electrode 466 f; elements 464 g, 464 h are separated by shimelectrode 466 g; shim electrode 466 h is adjacent element 464 h; andshim electrode 466 i is adjacent element 464 a. The positive connectionfor both frequencies f1, f2 (+f1/f2) is provided to the shim electrodes466 a, 466 c, 466 e, and 466 g. The negative connection for bothfrequencies f1, f2 (−f1/f2) is provided to shim electrodes 466 b, 466 d,466 f, 466 h, and 466 i, where the negative connections may be groundedas desired.

FIG. 4H illustrates a driver for use in a transducer including a stackof piezoelectric elements 474 a, 474 b, 474 c, 474 d, 474 e, 474 f, 474g, and 474 h. Elements 474 a, 474 b are separated by shim electrode 476a; elements 474 b, 474 c are separated by shim electrode 476 b; elements474 c, 474 d are separated by shim electrode 476 c; elements 474 d, 474e are separated by shim electrode 476 d; elements 474 e, 474 f areseparated by shim electrode 476 e; elements 474 f, 474 g are separatedby shim electrode 476 f; elements 474 g, 474 h are separated by shimelectrode 476 g; shim electrode 476 h is adjacent element 474 h; andshim electrode 476 i is adjacent element 474 a. The positive connectionfor both frequencies f1, f2 (+f1/f2) is provided to the shim electrodes476Aa, 476 c, 476 e, and 476 g. The negative connection for bothfrequencies f1, f2 (+−f1/f2) is provided to shim electrodes 476 b, 476d, 476 f, 476 h, and 476 i, where the negative connections may begrounded as desired.

FIG. 4I illustrates a driver for use in a transducer including a stackof piezoelectric elements 484 a, 484 b, 484 c, 484 d, 484 e, 484 f, 484g, and 484 h. Elements 484 a, 484 b are separated by shim electrode 486a; elements 484 b, 484 c are separated by shim electrode 486 b; elements484 c, 484 d are separated by shim electrode 486 c; elements 484 d, 484e are separated by shim electrode 486 d; elements 484 e, 484 f areseparated by shim electrode 486 e; elements 484 f, 484 g are separatedby shim electrode 486 f; elements 484 g, 484 h are separated by shimelectrode 486 g; shim electrode 486 h is adjacent element 484 h; andshim electrode 486 i is adjacent element 484 a. The positive connectionfor both frequencies f1, f2 (+f1/f2) is provided to the shim electrodes486 a, 486 c, 486 e, and 486 g. The negative connection for bothfrequencies f1, f2 (−f1/f2) is provided to shim electrodes 486 b, 486 d,486 f, 486 h, and 486 i, where the negative connections may be groundedas desired.

FIG. 4J illustrates a driver for use in a transducer including a stackof piezoelectric elements 494 a, 494 b, 494 c, 494 d, 494 e, 494 f, 494g, and 494 h. Elements 494 a, 494 b are separated by shim electrode 496a; elements 494 b, 494 c are separated by shim electrode 496 b; elements494 c, 494 d are separated by shim electrode 496 c; elements 494 d, 494e are separated by shim electrode 496 d; elements 494 e, 494 f areseparated by shim electrode 496 e; elements 494 f, 494 g are separatedby shim electrode 496 f; elements 494 g, 494 h are separated by shimelectrode 496 g; shim electrode 496 h is adjacent crystal 494 h; andshim electrode 496 i is adjacent element 494 a. The positive connectionfor frequency f1 (+f1) is provided to the electrodes 496 a and 496 g.The positive connection for frequency f2 (+f2) is provided to the shimelectrodes 496 c and 496 e. The negative connection for both frequenciesf1, f2 (−f1/f2) is provided to shim electrodes 496 b, 496 d, 496 f, 496h, and 496 i, where the negative connections may be grounded as desired.

Certain aspects of the present invention have been described inconnection with piezoelectric elements having split electrodes (such asFIGS. 2A-2C and 3A-3C), but the piezoelectric element body is not split.However, in certain exemplary embodiments of the present invention, theentire piezoelectric element body may be split in two (or more) pieces.For example, in the illustration provided in FIGS. 5A-5B, eachpiezoelectric element has been split (as indicated by the solidcenterline on each element). That is, element 304 a has been split into304 a 1 and 304 a 2, etc. Additionally, the left hand portion of eachelement has been “flipped” around. For example, element portion 304 a 1(and element portions 304 b 1, 304 c 1, and 304 d 1) has been flipped.Thus, by viewing the polarity markings (the “+” and “−” symbols) in FIG.5A, it is clear that the right hand portion of each piezoelectricelement is reversed in comparison to the left hand portion of eachelement. FIG. 5B also illustrates an exemplary electrical connection forthe stack of FIG. 5A whereby the positive connection for f1 and f2(+f1/f2) is coupled to two of the shim electrodes (306 a, 306 c), whilethe negative connection for f1 and f2 (−f1/f2) are coupled to others ofthe electrodes (306 b, 306 d, and 306 e via a ground connection ifdesired). Thus, in this example, electrical energy at both frequenciesis provided simultaneously. In any event, the configuration illustratedin FIGS. 5A-5B provides a non-linear scrub to the bonding tool tip.

FIGS. 6A and 6B are additional exemplary embodiments of the presentinvention which combine certain of the aforementioned concepts.Referring specifically to FIG. 6A, the upper two piezoelectric elementsare split (with the left hand portions flipped). A first frequency f1(e.g., 115 kHz) is applied and generates a tool tip scrub in a firstdirection (e.g., along the X-axis). The lower two piezoelectric elementsare standard elements (i.e., they have not been split, and theirelectrodes have not been split), and a second frequency f2 (e.g., 120kHz) is applied and generates a tool tip scrub in a second direction(e.g., along the Y-axis). This arrangement may have certain benefits,for example, it completely uncouples the f1 and f2 modes (i.e., the backEMF cancels in each case). More specifically, when the upper portion isdriven at frequency f1, the lower piezoelectric elements will notproduce a back EMF charge at f1 because the charge cancels when the leftside of the crystal deforms out of phase with the right side of thepiezoelectric element. When the bottom portion is driven at frequencyf2, the back EMF at f2 cancels in the top two piezoelectric elementssince the charge cancels when the left and right sides move in phase.

FIG. 6B is yet another exemplary configuration. In FIG. 6B, the upperpiezoelectric elements are split as in FIG. 6A, and now the lower twopiezoelectric elements have split electrodes (as in FIGS. 2A-2C and3A-3C). Additionally, the electrode between the third and fourthpiezoelectric elements is split (i.e., has two electrically isolatedregions). Of course, FIG. 6B is just one of a number of variations ofthe teachings of the present invention.

FIGS. 7A-7C illustrate non-linear scrub patterns of a bonding tool tipgenerated by a transducer/operating technique of the present invention.As described above, various exemplary embodiments of the presentinvention are drawn to providing a non-linear scrub of the bonding tooltip. A Lissajous scrub pattern is an example of such a scrub pattern andmay include circular scrub patterns, elliptical scrub patterns, or meshshaped scrub patterns. Of course, other non-linear scrub patterns arecontemplated.

The present invention is primarily described in connection with a piezostack of four or eight piezoelectric elements, and two frequenciesapplied thereto (e.g., f1 and f2, or f1/f2). It is understood thatdifferent stack arrangement (with more or less piezoelectric elements)and different frequencies (e.g., more than two electrical signals, suchas the inclusion of a third signal at frequency f3) are contemplated.

Various aspects of the present invention are described in connectionwith “split” piezoelectric elements and split piezoelectric element“electrodes.” It is understood that the structures (e.g., thepiezoelectric elements, the piezoelectric element electrodes, the shimselectrodes, etc.) may be physically altered (e.g., cut) to provide thedesired electrical isolation. However, the splitting may be provided inother ways such as when the structures are first manufactured they maybe provided with the desired electrically isolated regions. Further, aswill be understood by those skilled in the art, the “poling” of thepiezoelectric elements (e.g., giving the elements their polarity, forexample, by applying a relatively high voltage such as 2,000 volts) maybe accomplished prior to, during, or after the splitting of the elementsor the splitting of the electrodes of the elements.

While the present invention has primarily been described in connectionwith transducers for providing non-linear scrubbing of a bonding tooltip, and for providing selective linear scrubbing of a bonding tool tip,it is not limited thereto. Certain of the teachings of the presentinvention may be used in connection with: (1) scrubbing motions havingnon-planar components (e.g., where at least a portion of the motion isnot in the XY plane, but is rather along the vertical Z-axis—see thelegend in FIG. 1, e.g.); and (2) torsional/spinning motions of thebonding tool tip (with or without scrubbing motions), amongst others.

While certain exemplary embodiments of the present invention have beendescribed in connection with piezoelectric elements (e.g., crystals,ceramics, etc.) split into two pieces, piezoelectric element electrodessplit into two pieces, and shim electrodes (e.g., shims) split into twopieces, it is understood that any of these may be divided into two ormore regions. That is, piezoelectric elements, piezoelectric elementelectrodes, and shim electrodes may be divided into two or moreelectrically isolated regions as desired in the given application.

Although the present invention has been illustrated and describedprimarily with respect to ultrasonic transducers for use in wire bondingmachines it is not limited thereto. For example, the teachings of thepresent invention (e.g., including piezoelectric element configurations,split elements, split element electrodes, stack arrangements, etc.) maybe applied to ultrasonic transducers for use in any of a number ofapplications such as ultrasonic imaging, ultrasonic sensors, ultrasonicwelders, ultrasonic motors, amongst others.

Although the invention is illustrated and described herein withreference to specific embodiments, the invention is not intended to belimited to the details shown. Rather, various modifications may be madein the details within the scope and range of equivalents of the claimsand without departing from the invention.

1. A method of forming a wire bond using a bonding tool coupled to atransducer of a wire bonding machine, the transducer including a driver,the method comprising the steps of: (1) applying electrical energy tothe driver at a first frequency; and (2) applying electrical energy tothe driver at a second frequency concurrently with the application ofthe electrical energy at the first frequency, the first frequency andthe second frequency being different from one another.
 2. The method ofclaim 1 wherein step (1) includes applying the electrical energy to thedriver at the first frequency of approximately 115 kHz.
 3. The method ofclaim 1 wherein step (2) includes applying the electrical energy to thedriver at the second frequency of approximately 120 kHz.
 4. The methodof claim 1 wherein step (1) includes applying the electrical energy tothe driver at the first frequency of approximately 115 kHz, and step (2)includes applying the electrical energy to the driver at the secondfrequency of approximately 120 kHz.
 5. The method of claim 1 furthercomprising the step of providing the driver to include a plurality ofpiezoelectric elements, each of the plurality of piezoelectric elementsbeing separated into at least two regions electrically isolated from oneanother.
 6. The method of claim 5 wherein step (1) includes applying theelectrical energy at the first frequency to a first of the at least tworegions of each of the plurality of piezoelectric elements, and step (2)includes applying the electrical energy at the second frequency to asecond of the at least two regions of each of the plurality ofpiezoelectric elements.
 7. The method of claim 5 wherein step (1)includes applying electrical energy at the first frequency and thesecond frequency to a first of the at least two regions of each of theplurality of piezoelectric elements, and step (2) includes applyingelectrical energy at the first frequency and the second frequency to asecond of the at least two regions of each of the plurality ofpiezoelectric elements.
 8. The method of claim 7 wherein the electricalenergy applied to the first region and the second region at the firstfrequency are in phase with one another, and the electrical energyapplied to the first region and the second region at the secondfrequency are out of phase with one another.
 9. The method of claim 1wherein the application of the electrical energy to the driver at thefirst frequency and the second frequency results in a non-linear scrubby a tip of the bonding tool.
 10. The method of claim 1 wherein thedriver includes at least one piezoelectric element configured to deformin a first direction upon the application of electrical energy, and atleast one piezoelectric element configured to deform in a seconddirection upon the application of electrical energy, the first directionand second direction being different from one another.
 11. The method ofclaim 10 wherein the first direction is along an X-axis of the wirebonding machine and the second direction is along a Y-axis of the wirebonding machine.
 12. The method of claim 10 wherein the first directionis along an X-axis of the wire bonding machine and the second directionis an XY shear direction.
 13. The method of claim 10 wherein the firstdirection is along a Y-axis of the wire bonding machine and the seconddirection is an XY shear direction.
 14. The method of claim 10 whereinthe at least one piezoelectric element configured to deform in the firstdirection deforms in the first direction upon the application ofelectrical energy at the first frequency, and the at least onepiezoelectric element configured to deform in the second directiondeforms in the second direction upon the application of electricalenergy at the second frequency.
 15. The method of claim 10 whereindeformation of the at least one piezoelectric element configured todeform in the first direction results in a scrub of a bonding tool tipalong an X-axis of the wire bonding machine, and deformation of the atleast one piezoelectric element configured to deform in the seconddirection results in a scrub of a bonding tool tip along a Y-axis of thewire bonding machine.
 16. A method of forming a wire bond using abonding tool coupled to a transducer of a wire bonding machine, thetransducer including a driver, the method comprising the steps of: (1)applying electrical energy to the driver at a first frequency to drive atip of the bonding tool in a first direction; and (2) applyingelectrical energy to the driver at a second frequency to drive a tip ofthe bonding tool in a second direction, the first direction beingdifferent than the second direction.
 17. The method of claim 16 whereinthe application of the electrical energy to the driver at the firstfrequency is concurrent with the application of the electrical energy tothe driver at the second frequency.
 18. The method of claim 16 whereinthe application of the electrical energy to the driver at the firstfrequency is not concurrent with the application of the electricalenergy to the driver at the second frequency.
 19. The method of claim 16wherein step (1) includes applying the electrical energy to the driverat the first frequency of approximately 115 kHz.
 20. The method of claim16 wherein step (2) includes applying the electrical energy to thedriver at the second frequency of approximately 120 kHz.
 21. The methodof claim 16 wherein step (1) includes applying the electrical energy tothe driver at the first frequency of approximately 115 kHz, and step (2)includes applying the electrical energy to the driver at the secondfrequency of approximately 120 kHz.
 22. The method of claim 16 whereinthe application of the electrical energy in step (1) results in a scrubof the tip of the bonding tool substantially along an X-axis of the wirebonding machine, and wherein the application of the electrical energy instep (2) results in a scrub of the tip of the bonding tool substantiallyalong a Y-axis of the wire bonding machine.
 23. The method of claim 16wherein further comprising the step of providing the driver to include aplurality of piezoelectric elements, each of the plurality ofpiezoelectric elements being separated into at least two regionselectrically isolated from one another.
 24. The method of claim 23wherein step (1) includes applying the electrical energy at the firstfrequency to a first of the at least two regions of each of theplurality of piezoelectric elements, and step (2) includes applying theelectrical energy at the second frequency to a second of the at leasttwo regions of each of the plurality of piezoelectric elements.
 25. Themethod of claim 23 wherein step (1) includes applying electrical energyat the first frequency and the second frequency to a first of the atleast two regions of each of the plurality of piezoelectric elements,and step (2) includes applying electrical energy at the first frequencyand the second frequency to a second of the at least two regions of eachof the plurality of piezoelectric elements.
 26. The method of claim 25wherein the electrical energy applied to the first region and theelectrical energy applied to the second region at the first frequencyare in phase with one another, and the electrical energy applied to thefirst region and the electrical energy applied to the second region atthe second frequency are out of phase with one another.
 27. The methodof claim 16 wherein the application of the electrical energy to thedriver at the first frequency and the second frequency results in anon-linear scrub by a tip of the bonding tool.
 28. The method of claim16 wherein the driver includes at least one piezoelectric elementconfigured to deform in a first direction upon the application of theelectrical energy at the first frequency, and at least one piezoelectricelement configured to deform in the second direction upon theapplication of the electrical energy at the second frequency, the firstdirection and the second direction being different from one another. 29.The method of claim 28 wherein the first direction is along an X-axis ofthe wire bonding machine and the second direction is along a Y-axis ofthe wire bonding machine.
 30. The method of claim 28 wherein the firstdirection is along an X-axis of the wire bonding machine and the seconddirection is an XY shear direction.
 31. The method of claim 28 whereinthe first direction is along an Y-axis of the wire bonding machine andthe second direction is an XY shear direction.
 32. A transducer for usein a wire bonding operation, the transducer comprising: (a) an elongatedbody portion configured to support a bonding tool; and (b) a driver forproviding vibration to the elongated body portion, the driver includinga plurality of piezoelectric elements, each of the plurality ofpiezoelectric elements being separated into at least two regionselectrically isolated from one another.
 33. The transducer of claim 32wherein electrical energy at a first frequency is configured to beapplied to a first of the at least two regions of each of the pluralityof piezoelectric elements, and electrical energy at a second frequencyis configured to be applied to a second of the at least two regions ofeach of the plurality of piezoelectric elements.
 34. The method of claim33 wherein the application of the electrical energy to the driver at thefirst frequency and the second frequency results in a non-linear scrubby a tip of the bonding tool.
 35. The transducer of claim 33 wherein thefirst frequency is approximately 115 kHz and the second frequency isapproximately 120 kHz.
 36. The transducer of claim 33 whereinapplication of the electrical energy at the first frequency to the firstregion results in a scrub of a tip of the bonding tool in a firstdirection, and wherein application of the electrical energy at thesecond frequency to the second region results in a scrub of a tip of thebonding tool in a second direction, the first direction being differentfrom the second direction.
 37. The transducer of claim 36 wherein thefirst direction extends along an X-axis of a wire bonding machine, andthe second direction extends along a Y-axis of the wire bonding machine.38. The transducer of claim 36 wherein the first direction extendssubstantially parallel to a longitudinal axis of the transducer, and thesecond direction extends substantially perpendicular to the longitudinalaxis of the transducer.
 39. The transducer of claim 36 wherein the firstdirection is substantially perpendicular to the second direction. 40.The transducer of claim 32 wherein electrical energy at a firstfrequency and a second frequency is configured to be applied to a firstof the at least two regions of each of the plurality of piezoelectricelements, and electrical energy at the first frequency and the secondfrequency is configured to be applied to a second of the at least tworegions of each of the plurality of piezoelectric elements.
 41. Thetransducer of claim 40 wherein the electrical energy applied to thefirst region and the second region at the first frequency are in phasewith one another, and the electrical energy applied to the first regionand the second region at the second frequency are out of phase with oneanother.
 42. The transducer of claim 32 wherein the body portion definesa driver aperture, and the plurality of piezoelectric elements arepositioned in the driver aperture.
 43. The transducer of claim 32wherein the plurality of piezoelectric elements includes at least onepiezoelectric element configured to deform in a first direction upon theapplication of electrical energy, and at least one piezoelectric elementconfigured to deform in a second direction upon the application ofelectrical energy, the first direction and second direction beingdifferent from one another.
 44. A transducer for use in a wire bondingoperation, the transducer comprising: (a) an elongated body portionconfigured to support a bonding tool; and (b) a driver for providingvibration to the elongated body portion, the driver being configured toreceive electrical energy and to provide a non-linear scrub of a tip ofthe bonding tool.
 45. The transducer of claim 44 wherein the driverincludes a plurality of piezoelectric elements, each of the plurality ofpiezoelectric elements being separated into at least two regionselectrically isolated from one another.
 46. The transducer of claim 45wherein electrical energy at a first frequency is configured to beapplied to a first of the at least two regions of each of the pluralityof piezoelectric elements, and electrical energy at a second frequencyis configured to be applied to a second of the at least two regions ofeach of the plurality of piezoelectric elements.
 47. The transducer ofclaim 46 wherein the first frequency is approximately 115 kHz and thesecond frequency is approximately 120 kHz.
 48. The transducer of claim46 wherein (1) application of the electrical energy at the firstfrequency to the first region, without application of the electricalenergy at the second frequency to the second region, results in a scrubof the tip of the bonding tool in a first direction, (2) application ofthe electrical energy at the second frequency to the second region,without application of the electrical energy at the first frequency tothe first region, results in a scrub of the tip of the bonding tool in asecond direction, the first direction being different from the seconddirection, and (3) application of the electrical energy at the firstfrequency to the first region and application of the electrical energyat the second frequency to the second region results in the non-linearscrub of the tip of the bonding tool.
 49. The transducer of claim 48wherein the first direction extends along an X-axis of a wire bondingmachine, and the second direction extends along a Y-axis of the wirebonding machine.
 50. The transducer of claim 48 wherein the firstdirection extends substantially parallel to a longitudinal axis of thetransducer, and the second direction extends substantially perpendicularto the longitudinal axis of the transducer.
 51. The transducer of claim48 wherein the first direction is substantially perpendicular to thesecond direction.
 52. The transducer of claim 48 wherein electricalenergy at a first frequency and a second frequency is configured to beapplied to a first of the at least two regions of each of the pluralityof piezoelectric elements, and electrical energy at the first frequencyand the second frequency is configured to be applied to a second of theat least two regions of each of the plurality of piezoelectric elements.53. The transducer of claim 52 wherein the electrical energy applied tothe first region and the second region at the first frequency are inphase with one another, and the electrical energy applied to the firstregion and the second region at the second frequency are out of phasewith one another.
 54. The transducer of claim 44 wherein the non-linearscrub follows a Lissajous pattern.
 55. The transducer of claim 44wherein the non-linear scrub follows a circular pattern.
 56. Thetransducer of claim 44 wherein the non-linear scrub follows anelliptical pattern.
 57. The transducer of claim 44 wherein thenon-linear scrub follows a mesh-shaped pattern.
 58. The transducer ofclaim 44 wherein the driver includes at least one piezoelectric elementconfigured to deform in a first direction upon the application ofelectrical energy, and at least one piezoelectric element configured todeform in a second direction upon the application of electrical energy,the first direction and second direction being different from oneanother.
 59. The transducer of claim 58 wherein the first direction isalong an X-axis of a wire bonding machine and the second direction isalong a Y-axis of the wire bonding machine.
 60. The transducer of claim58 wherein the first direction is along an X-axis of a wire bondingmachine and the second direction is an XY shear direction.
 61. Thetransducer of claim 58 wherein the first direction is along an Y-axis ofa wire bonding machine and the second direction is an XY sheardirection.
 62. The transducer of claim 58 wherein the at least onepiezoelectric element configured to deform in the first directiondeforms in the first direction upon the application of electrical energyat a first frequency, and the at least one piezoelectric elementconfigured to deform in the second direction deforms in the seconddirection upon the application of electrical energy at a secondfrequency, the first frequency being different from the secondfrequency.
 63. The transducer of claim 44 wherein the body portiondefines a driver aperture, and the plurality of piezoelectric elementsare positioned in the driver aperture.
 64. A transducer for use in awire bonding operation, the transducer comprising: (a) an elongated bodyportion configured to support a bonding tool; and (b) a driver forproviding vibration to the elongated body portion, the driver includingat least one piezoelectric element configured to deform in a firstdirection upon the application of electrical energy, and at least onepiezoelectric element configured to deform in a second direction uponthe application of electrical energy, the first direction and seconddirection being different from one another.
 65. The transducer of claim64 wherein the at least one piezoelectric element configured to deformin the first direction deforms in the first direction upon theapplication of electrical energy at a first frequency, and the at leastone piezoelectric element configured to deform in the second directiondeforms in the second direction upon the application of electricalenergy at a second frequency, the first frequency being different fromthe second frequency.
 66. The transducer of claim 64 wherein the firstdirection is along an X-axis of a wire bonding machine and the seconddirection is along a Y-axis of the wire bonding machine.
 67. Thetransducer of claim 64 wherein the first direction is along an X-axis ofa wire bonding machine and the second direction is an XY sheardirection.
 68. The transducer of claim 64 wherein the first direction isalong an Y-axis of a wire bonding machine and the second direction is anXY shear direction.
 69. The transducer of claim 65 wherein the firstfrequency is approximately 115 kHz and the second frequency isapproximately 120 kHz.
 70. The transducer of claim 65 wherein (1)application of the electrical energy at the first frequency, withoutapplication of the electrical energy at the second frequency, results ina scrub of the tip of the bonding tool in a first direction, (2)application of the electrical energy at the second frequency, withoutapplication of the electrical energy at the first frequency, results ina scrub of the tip of the bonding tool in a second direction, the firstdirection being different from the second direction, and (3) applicationof the electrical energy at the first frequency and the second frequencyresults in the non-linear scrub of the tip of the bonding tool.
 71. Thetransducer of claim 70 wherein the first direction of the scrub extendsalong an X-axis of a wire bonding machine, and the second direction ofthe scrub extends along a Y-axis of the wire bonding machine.
 72. Thetransducer of claim 70 wherein the first direction of the scrub extendssubstantially parallel to a longitudinal axis of the transducer, and thesecond direction of the scrub extends substantially perpendicular to thelongitudinal axis of the transducer.
 73. The transducer of claim 70wherein the first direction of the scrub is substantially perpendicularto the second direction of the scrub.
 74. The transducer of claim 64wherein the first direction and second direction are substantiallyperpendicular to one another.
 75. The transducer of claim 64 wherein thebody portion defines a driver aperture, and the plurality ofpiezoelectric elements are positioned in the driver aperture.